The present invention relates to a circular friction lining carrier member with replaceable friction linings, in particular, for clutch-type disc brakes having the friction linings guided and held captive radially inwardly and outwardly in circumferential grooves and a separating or supporting element arranged between each of the friction linings.
A friction lining carrier member of this type is known from German Pat. DE-OS No. 2,100,009. The grooves of the friction lining carrier member forming the guidance are of dove-tailed cross section. The guidance has disposed thereacross separating or supporting elements which are rigidly connected to the friction lining carrier member and have a radially extending groove open relative to the guidance. More particularly, two friction linings are placed in the guidance communicating with each other via a conical separating element situated in the guidance. The conical separating element is constructed such that its radially extending rims intersect in the central point of the circle assigned to the circular segment. In addition to this, the separating element includes radially extending grooves open relative to the guidance resulting in the friction linings being positioned with their entire periphery in a groove. To accomplish this, the friction linings are chamfered at all four edges and are of a trapezoidal configuration. The friction linings are inserted in the friction lining carrier member in such a way as to be positioned with their entire periphery fixed without clearance in the dove-tailed grooves.
Since the separating element is constructed as a sector of a circular ring having the same radius as the friction lining carrier member and the friction linings disposed thereon manufacture of the parts entails great expenditure of time and effort resulting in high costs. Since the end surface of the separating element and an end surface of a friction lining have to abut each other without clearance, high requirements regarding manufacturing accuracy have to be met which has impeded mass production.
Furthermore, friction linings are subjected to different mechanical loads. When a circular-like friction lining carrier member having friction linings disposed thereon is brought in frictional engagement with a disc rotating in the main direction of rotation, the friction linings will transmit the friction forces occurring onto that clamping element lying in the rear of the friction lining when looking towards the main direction of rotation. In this structure, the friction lining directly adjacent to the clamping element will have to transmit all circumferential forces of all of the friction linings inserted ahead of it, since the separating elements are not connected to the friction lining carrier member in the circumferential direction. Thus, the friction lining closest to the clamping element is required to transmit all circumferential forces occurring. Due to this increased mechanical load, this friction lining is subjected to greater wear resulting in the friction volume available at the other linings not being permitted to be fully utilized. This disadvantage will have a greater effect as the number of individual friction linings disposed on the friction lining carrier member is increased. Moreover, the clamping element receiving the braking forces has to be fixed to the friction lining carrier member in a particularly costly manner to provide transmission of the braking forces without the clamping element being torn out of its anchor.
A different arrangement of several friction linings on a friction lining carrier member is described in German Pat. DE-PS No. 927,905. The friction linings are rigidly arranged on backing plates, with the backing plates including mechanisms in the circumferential direction, by which they are fastened to mechanisms on the friction lining carrier member. Each single fastening mechanism has to be secured against detachment which increases the expenditure for such an arrangement considerably. Since the backing plate is of relatively thin design in such an arrangement, a so-called bimetal effect will occur in the event of a braking operation having a great thermal conversion of energy, since the friction lining, its backing plate and the friction lining carrier member will warm up and differing coefficients of thermal expansion are normally prevailing. Due to this, the friction lining will be curved axially so that it is not possible to urge the entire surface of the friction lining into frictional engagement with the disc. A partial wear of the friction lining is the result. In addition, the bimetal effect leads to a separation of friction lining and carrier member material and, thus, to a premature total detachment of the friction lining material, and as a consequence a complete failure of the brake.